Arakimunisai Ryu Iaido is an ancient sword school dating back to 1559 and a young samurai, Araki Mujinsai Minamoto Hidetsuna, grandson of Araki Setsu no Kami Minamoto Murashige of Itami Castle in the Settsu district (now Hyogo prefecture) in Western Honshu near present day Osaka and Kyoto.

He joined the army of Hideyoshi Toyotomi as part of the latter’s invasion plans for Korea and distinguished himself in battle in 1591. By way of reward Toyotomi awarded him the name of Nippon Kaizan in tribute to his remarkable fightling ability.

Details of his birth and death are unclear, but he is known to have learned both kogusoku (military fighting arts) and Takenouchi Ryu and he lived in Araki Mura, Nanjo Gun, Fukui prefecture just north of Kyoto. His own style was founded upon his combat experiences and is said to be one of the three oldest budo (traditional fighting arts).

His memory is enshrined in the name of the school.

An unbroken line of headmasters has ensured that the style has remained unchanged (and is thus considered jikiden or pure). The present headmaster (soke) is the 16th in line.